129 lines
3.3 KiB
Java
129 lines
3.3 KiB
Java
package VL05.Aufgabe02;
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/**
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* Vorlesung 5 / Aufgabe 2
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*
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* @author Sebastian Brosch
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*/
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public class Aufgabe02 {
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public static void main(String[] args) {
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final int DAMEN = 8;
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int chessboard[][] = new int[DAMEN][DAMEN];
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queens(chessboard, 1);
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}
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/**
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* Method to place a queen on the chessboard.
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*
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* @param chessboard The chessboard to place the queen.
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* @param q The number of the queen to be placed.
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*/
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private static void queens(int[][] chessboard, int q) {
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if (q > chessboard.length) {
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print(chessboard);
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return;
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} else {
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for (int i = 0; i < chessboard.length; i++) {
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if (isQueenPossible(chessboard, q - 1, i)) {
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chessboard[q - 1][i] = 1;
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queens(chessboard, q + 1);
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chessboard[q - 1][i] = 0;
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}
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}
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}
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}
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/**
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* Method to check whether a queen can be placed on the field.
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*
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* @param chessboard The chessboard to place the queen.
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* @param row The row to place the queen.
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* @param column The column to place the queen.
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* @return The state whether the queen can be placed on the field.
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*/
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private static boolean isQueenPossible(int[][] chessboard, int row, int column) {
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int currentRow = 0;
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int currentColumn = 0;
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// check whether the queen can be placed in current row.
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for (int c = 0; c < chessboard[row].length; c++) {
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if (chessboard[row][c] == 1)
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return false;
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}
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// check whether the queen can be placed in current column.
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for (int r = 0; r < chessboard.length; r++) {
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if (chessboard[r][column] == 1)
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return false;
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}
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// check whether the queen can be placed diagonal (top left).
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currentRow = row;
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currentColumn = column;
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while (currentColumn >= 0 && currentRow >= 0) {
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if (chessboard[currentRow][currentColumn] == 1)
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return false;
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currentRow--;
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currentColumn--;
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}
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// check whether the queen can be placed diagonal (bottom right).
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currentRow = row;
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currentColumn = column;
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while (currentColumn < chessboard[row].length && currentRow < chessboard.length) {
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if (chessboard[currentRow][currentColumn] == 1)
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return false;
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currentRow++;
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currentColumn++;
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}
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// check whether the queen can be placed diagonal (bottom left).
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currentRow = row;
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currentColumn = column;
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while (currentColumn >= 0 && currentRow < chessboard.length) {
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if (chessboard[currentRow][currentColumn] == 1)
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return false;
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currentRow++;
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currentColumn--;
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}
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// check whether the queen can be placed diagonal (top right).
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currentRow = row;
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currentColumn = column;
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while (currentColumn < chessboard[row].length && currentRow >= 0) {
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if (chessboard[currentRow][currentColumn] == 1)
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return false;
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currentRow--;
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currentColumn++;
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}
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return true;
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}
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/**
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* Method to print a chessboard.
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*
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* @param chessboard The chessboard to be printed.
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*/
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private static void print(int[][] chessboard) {
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System.out.println("\nChessboard:\n");
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for (int r = 0; r < chessboard.length; r++) {
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for (int c = 0; c < chessboard[r].length; c++) {
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System.out.printf("%d", chessboard[r][c]);
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}
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System.out.printf("\n");
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}
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}
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}
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